252, 504, 756 . . .
252, 504, 756 and so on.
There are infinitely many of them so they cannot be listed. One of their multiples is 294*252*210 = 15558480.
The first 15 multiples of 252: 252, 504, 756, 1008, 1260, 1512, 1764, 2016, 2268, 2520, 2772, 3024, 3276, 3528, 3780 . . .
252 and its multiples.
252
84, 168, 252 and so on.
84, 168, 252.
Any multiple of 252.
84, 168, 252
No, they are factors.
126, 252, 378